| Fort Collins to Nuth | 4,873.07 mi (7,842.45 km) |
| Fort Collins to Oegstgeest | 4,769.93 mi (7,676.46 km) |
| Fort Collins to Oirschot | 4,827.59 mi (7,769.26 km) |
| Fort Collins to Oisterwijk | 4,820.59 mi (7,757.98 km) |
| Fort Collins to Oldebroek | 4,804.14 mi (7,731.52 km) |
| Fort Collins to Oldenzaal | 4,843.03 mi (7,794.10 km) |
| Fort Collins to Ommen | 4,817.55 mi (7,753.10 km) |
| Fort Collins to Oosterend | 4,784.45 mi (7,699.83 km) |
| Fort Collins to Oosterhout | 4,806.70 mi (7,735.64 km) |
| Fort Collins to Oosterwolde | 4,792.14 mi (7,712.20 km) |
| Fort Collins to Oostzaan | 4,772.30 mi (7,680.28 km) |
| Fort Collins to Opmeer | 4,762.57 mi (7,664.62 km) |
| Fort Collins to Oss | 4,822.63 mi (7,761.27 km) |
| Fort Collins to Oud-Beijerland | 4,784.02 mi (7,699.14 km) |
| Fort Collins to Oudenbosch | 4,798.20 mi (7,721.96 km) |
